The iPhone, iPod touch and particularly the iPad have continued to dramatically expand their abilities as music creation devices since the App Store debuted in 2008. Initially limited mostly to virtual instrument apps, Apple's introduction of Core MIDI support followed by an iOS version of Apple's own GarageBand music software solidified the iPad's status as a versatile and powerful tool for amateur and professional musicians alike.

For those who might not know the background details, here’s a brief primer. The Musical Instrument Digital Interface standard, more commonly known as MIDI, enables accessories such as electronic piano keyboards, synthesizers, and drum machines to interface with each other and computer software for recording and editing of compositions. Rather than sending out actual audio streams, MIDI devices operate by sharing digital information—notes, tempos, sound references, and volume levels—with one another. This information can be recorded and played back on MIDI hardware, or edited using a number of desktop computer applications. MIDI has also been expanded beyond traditional music and audio to include a wide array of other studio and performance equipment, such as stage lighting systems. Prior to the introduction of Core MIDI in November 2010, accessory manufacturers—and software developers—had to build proprietary MIDI solutions for iOS devices. Apple recognized the need for a standard method to address this increasingly common requirement, debuting Core MIDI in iOS 4.2 so MIDI hardware and iOS apps could easily communicate with each other.

iRig MIDI ($70) is IK Multimedia’s pocket-sized Core MIDI interface for connecting MIDI devices to an iPhone, iPod touch or iPad. Three MIDI ports are included: in addition to the standard MIDI IN and MIDI OUT connections, iRig MIDI also includes a MIDI THRU port for use with more sophisticated MIDI system configurations such as external sound modules and sequencers—a useful addition for professional musicians that isn’t commonly found on other similar accessories. The package also includes two 5-foot 2.5mm to 5-pin DIN MIDI cables, as well as a micro-USB charging port and cable to provide power to the iOS device for longer sessions. Two LEDs display activity on the MIDI IN and OUT channels.

To get users started, IK Multimedia provides two free companion iOS apps called SampleTank and iRig MIDI Recorder, though the iRig MIDI can also be used with any of the more than 100 Core MIDI-compliant apps on the App Store, including Apple’s GarageBand. Connecting the iRig MIDI to an iOS device the first time will provide the user with a prompt to go to the App Store and download the free iRig MIDI Recorder app.

iRig MIDI Recorder is a universal app that provides basic recording and playback of MIDI sequences from any external MIDI source when used with the accessory. The basic use is relatively straightforward: connect your external MIDI devices via the iRig MIDI, start the app and hit the “Record” button; by default, all received MIDI data will be recorded, and the resulting MIDI file can be exported via e-mail or iTunes File Sharing. It can also be downloaded with a browser via a direct Wi-Fi connection to the app.

iRig MIDI Recorder also provides several more advanced recording features, including the ability to monitor and/or filter out specific MIDI data types while recording, as well as limiting recording to only MIDI channel 1 instead of all 16 channels. An optional “Soft THRU” mode is also available that can be used to send all received MIDI data back out the MIDI OUT port at the same time as it is being recorded, effectively creating a second MIDI THRU port on the iRig MIDI. iRig MIDI Recorder is also used to manage and download firmware updates for the iRig MIDI device; the current firmware version of a connected accessory will be displayed at the bottom of the Setup screen.

In addition to the iRig MIDI Recorder, IK Multimedia also offers SampleTank in two versions, SampleTank Free and SampleTank ($20). They currently differ only in the number of included instruments and sounds; both SampleTank apps provide iRig MIDI users with a full-featured MIDI workstation tool for iOS devices. Four-channel MIDI sequencing is provided alongside hundreds of realistic instruments and sound patterns, allowing musicians to use the app as either a sound/synth module for live performances, or for creating and saving multi-track recordings.

IK’s full version of SampleTank provides access to an expandable set of over 500 instruments organized across 16 different categories, providing a wealth of acoustic, electric and electronic sounds. Each category also includes dozens of instrument riffs and grooves for a total of over 1,000 patterns to choose from for backing purposes. While the free version of SampleTank includes 8 instruments and over 1,000 patterns, the $20 version comes bundled with additional sounds for 136 instruments in total. Users of either version can add more Sound Packs via in-app purchase for $2, $5, or $10 per pack, or a flat rate of $40 for the full set of 22; however, free app users still need to pay $20 more to get 64 instruments that are unique to the full app, and not included in the sound packs. Existing instruments and sounds can also be customized with adjustments for volume, pan, filter cutoff frequency, filter resonance and envelope attack and release, as well as instrument-specific effects settings; customizations can be saved in 96 available user presets.

SampleTank can handle up to four MIDI channels simultaneously with different instruments or sounds assigned to each channel. Input from external MIDI devices is reflected in real-time, with on-screen keyboard and controllers indicating the MIDI notes and commands as they are being received. Users can also record up to four independent tracks via MIDI input, or using the virtual keyboard and drum pads in the app itself; existing tracks can also be overdubbed with additional layers. Recordings can be exported to a universally playable M4A format via e-mail or iTunes File Sharing.

SampleTank provides a multitude of advanced features for both serious amateur and professional musicians, including virtual standard and scale keyboards along with an enhanced, user-assignable drum pad interface with full multi-touch support; both keyboards and drum pads can be used to perform or record alongside external instruments via the iRig MIDI interface. The app also includes latency, level and velocity curve adjustments, advanced audio dock support, quantization and custom MIDI channel assignment for each track. In addition to the 96 user-assignable presets, 24 factory presets are also included to demonstrate the various instruments and sounds available.

IK Multimedia includes a stunning array of instruments and sounds and professional grade MIDI workstation features within SampleTank, and the free version is definitely worth checking out. Before you spend $20 on the full version, it’s worth noting that Apple’s highly-acclaimed GarageBand for iOS (iLounge Rating: A) will be a viable alternative for many users at a lower price. iRig MIDI is a great companion for GarageBand, which provides a very intuitive, user-friendly interface that may be more appealing for amateur musicians who simply want to play around with basic MIDI equipment and have no need for the more sophisticated features and much wider array of instruments and sounds provided by SampleTank. On the other hand, serious amateur and professional musicians will find SampleTank to be a much more powerful and versatile tool for both live performances and laying down multi-track recordings. The only major downside with SampleTank is the pricing model; while the idea of a flexible “buy-only-what-you-need” structure is very attractive, we found the current set of options across two different versions of the app to be needlessly confusing.

Ultimately, the iRig MIDI is an extremely capable MIDI interface for iOS devices. For basic MIDI features, it works exactly as expected, but also offers unique features such as MIDI THRU and external power support within an ultra-portable and relatively inexpensive device. Core MIDI support also ensures compatibility with a plethora of third-party apps; a list of just some of the compatible apps can also be found on the company’s web site, providing users with a vast array of options beyond IK Multimedia’s own very capable iRig MIDI Recorder and SampleTank apps. The iRig MIDI accessory is worthy of our high recommendation with only modest caveats on the software end; users of GarageBand will be particularly thrilled by what it adds to Apple’s already amazing software.

Editors' Note: iLounge only reviews products in "final" form, but many companies now change their offerings - sometimes several times - after our reviews have been published.
This iLounge article provides more information on this practice, known as revving.